My plan is to use HR in the process of polar aligning the camera for astrophotography.
I want to zoom in the HR live view screen as much as possible and keep track of a specific star. The HR feature "show 10x10 grid" would be perfect for this, but the grid disappears from the live view screen the moment I start zooming. Would it be possible to continue the grid overlay during zooming ? It would be a great improvement.

That's not hard to do, but we don't want to make this change, we think the grid should be consistent with the image. What we can do is make this adjustment for you personally. What operating system are you using Remote on?